United States: Hepatitis B on Decline but Many Still at Risk

New cases of hepatitis B have decreased substantially in recent years, but widespread programs to vaccinate high-risk adults, according to a study, could reduce the incidence even further. "The [report] is an indication of how successful we've been with our prevention programs and where we need to focus our efforts in the future," said study author Miriam J. Alter, an epidemiologist at the CDC.

CDC researchers worked with local public health officials in four US counties -- Denver County, Colo.; Pierce County, Wash.; Jefferson County, Ala.; and Pinellas County, Fla. -- to gather detailed information on adults and children infected with hepatitis B from 1982, when the hepatitis B vaccine became available, to 1998. The researchers chose these counties because they are representative of the general population.

Results published in the Journal of Infectious Diseases (2002;185;6:713-719) showed that while infection rates fluctuated somewhat until 1987, when they peaked, they declined 76 percent between 1987 and 1998, from 13.8 cases per 100,000 people to 3.3 cases per 100,000.

Some of the declines among heterosexuals engaging in risky sex -- the population most at risk -- may have been due to an increase in safe sexual practices. Vaccination, most likely among health care workers, is also credited. Sharp drops among injection drug users were more difficult to explain, since few were vaccinated, according to the authors. One explanation is that needle exchange programs helped reduce the spread of the virus. Another possibility is that the "reservoir" for the virus shrank due to people dying from AIDS or being jailed for drug possession. Declines among gay men from 1982 to 1986 were attributed to increased safe sex practices in response to the AIDS epidemic, though the number of new hepatitis B infections remained fairly static after that time.

More than half of infected people interviewed from 1996 to 1998 reported being treated for another STD or spending time in jail prior to diagnosis with hepatitis B, the study found. As a result, many hepatitis B infections could have been avoided if there were routine vaccinations both at STD clinics and jails, researchers said. "Our concern is that more than half of these cases could have been prevented if vaccinations had been given, as is recommended," Alter said. "A large part of the problem is that there is no federal funding for adults." There is federal funding to vaccinate children, she noted.

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